The End of All Things - S4-E14
Corrected entry: When David Robert Jones pulls the little box with the lights out, Olivia says that she knows what she has to do, that she "has to turn the lights on with her mind." She knows this because her memory of him returned, but she didn't have to turn the lights on. In the original episode she had to turn them off. (00:31:00)
Correction: Olivia never specifically said she has turned the lights on before, just that "we did something like this before"